List of nearest stars and brown dwarfs

The easiest way to determine stellar distance to the Sun for objects at these distances is parallax, which measures how much stars appear to move against background objects over the course of Earth's orbit around the Sun. As a parsec (parallax-second) is defined by the distance of an object that would appear to move exactly one second of arc against background objects, stars less than 5 parsecs away will have measured parallaxes of over 0.2 arcseconds, or 200 milliarcseconds. Determining past and future positions relies on accurate astrometric measurements of their parallax and total proper motions (how far they move across the sky due to their actual velocity relative to the Sun), along with spectroscopically determined radial velocities (their speed directly towards or away from us, which combined with proper motion defines their true movement through the sky relative to the Sun). Both of these measurements are subject to increasing and significant errors over very long time spans, especially over the several thousand-year time spans it takes for stars to noticeably move relative to each other.^[2]

Based on results from the Gaia telescope's second data release from April 2018, an estimated 694 stars will approach the Solar System to less than 5 parsecs in the next 15 million years. Of these, 26 have a good probability to come within 1.0 parsec (3.3 light-years) and another 7 within 0.5 parsecs (1.6 light-years).^[3] This number is likely much higher, due to the sheer number of stars needed to be surveyed; a star approaching the Solar System 10 million years ago, moving at a typical Sun-relative 20–200 kilometers per second, would be 600–6,000 light-years from the Sun at present day, with millions of stars closer to the Sun. The closest encounter to the Sun so far predicted is the low-mass orange dwarf star Gliese 710 / HIP 89825 with roughly 60% the mass of the Sun.^[4] It is currently predicted to pass 0.1696±0.0065 ly (10635±500 au) from the Sun in 1.290±0.04 million years from the present, close enough to significantly disturb the Solar System's Oort cloud.^[5]

The classes of the stars and brown dwarfs are shown in the color of their spectral types (these colors are derived from conventional names for the spectral types and do not necessarily represent the star's observed color). Many brown dwarfs are not listed by visual magnitude but are listed by near-infrared J band apparent magnitude due to how dim (and often invisible) they are in visible color bands (U, B or V). Absolute magnitude (with electromagnetic wave, 'light' band denoted in subscript) is a measurement at a 10-parsec distance across imaginary empty space devoid of all its sparse dust and gas. Some of the parallaxes and resultant distances are rough measurements.^[6]

Over long periods of time, the slow independent motion of stars change in both relative position and in their distance from the observer. This can cause other currently distant stars to fall within a stated range, which may be readily calculated and predicted using accurate astrometric measurements of parallax and total proper motions, along with spectroscopically determined radial velocities. Although predictions can be extrapolated back into the past or forward into the future, they are subject to increasing significant cumulative errors over very long periods.^[2] Inaccuracies of these measured parameters make determining the true minimum distances of any encountering stars or brown dwarfs fairly difficult.^[72]

One of the first stars known to approach the Sun particularly close is Gliese 710. The star, whose mass is roughly half that of the Sun, is currently 62 light-years from the Solar System. It was first noticed in 1999 using data from the Hipparcos satellite, and was estimated will pass less than 1.3 light-years (0.40 pc) from the Sun in 1.4 million years.^[73] With the release of Gaia's observations of the star, it has since been refined to a much closer 0.178 light-years (0.055 pc), close enough to significantly disturb objects in the Oort cloud, which extends out to 1.2 light-years (0.37 pc) from the Sun.^[74]

Gaia's third data release has provided updated values for many of the candidates in the table below.^{[75][76][77][78]}

Schematic view to scale of past and future close approaches of stars to the Sun (Up to 4.5 light-years)

Related lists

• "The 100 nearest star systems", Research Consortium on Nearby Stars
• "NStars database". Northern Arizona University. Archived from the original on October 30, 2005. Retrieved October 24, 2005.
• Nemiroff, R.; Bonnell, J., eds. (18 March 2001). "Map of the 25 nearest star systems". Astronomy Picture of the Day. NASA. Retrieved 24 October 2005.
• "Notable Nearby Stars". SolStation. Retrieved 24 October 2005.
• "Cool stars in the solar Neighbourhood". D. Montes, UCM. Retrieved 14 November 2005.
• The dynamics of the closest stars
• Takeda, G.; E. B. Ford; A. Sills; F. A. Rasio; D. A. Fischer; J. A. Valenti (2006). "Structure and Evolution of Nearby Stars with Planets II. Physical Properties of ~ 1000 Cool Stars from the SPOCS Catalog". California & Carnegie Planet Search. Retrieved 13 October 2006.
• Nearest Stars 3D View
• Table 4 "The Census of Stars and Brown Dwarfs within 8 Parsecs of the Sun" in Bailer-Jones, C. A. L.; et al. (2012). "Further Defining Spectral Type "Y" and Exploring the Low-mass End of the Field Brown Dwarf Mass Function". The Astrophysical Journal. 753 (2): 156. arXiv:1205.2122. Bibcode:2012ApJ...753..156K. doi:10.1088/0004-637X/753/2/156. S2CID 119279752.